/*

Example of using curl from C++.

About curl: http://curl.haxx.se/libcurl/c/

Compilation on Linux:
g++ -o curl-example -lcurl curl-example.cpp

*/

#include <iostream>
#include <sstream>
#include <string>
#include <curl/curl.h>

using std::cerr;
using std::cout;
using std::endl;
using std::string;
using std::stringstream;

// vvvvvvvvv start: could be moved to separate header-file vvvvvvvvv
class URL {

 private:
    CURL* curl;
    std::string url;

    void init_curl();
    static size_t curl_callback(void*,size_t,size_t,void*);

 public:

    URL(std::string);
    ~URL();
    void set_url(std::string);
    std::string get_url() const;
    std::string get_body() const;
};
// ^^^^^^^^^  end: could be moved to separate header-file  ^^^^^^^^^

URL::URL(string arg) {
    init_curl();
    set_url(arg);
}

URL::~URL() {
    curl_easy_cleanup(curl);
}

void URL::init_curl() {
    curl = curl_easy_init();
    if (0==curl) {
        cerr << "Couldn't initialize curl" << endl;
        exit(1);
    }
    curl_easy_setopt(curl,CURLOPT_WRITEFUNCTION, curl_callback);
}

void URL::set_url(string arg) {
    url=arg;
    curl_easy_setopt(curl, CURLOPT_URL, arg.c_str());
}

string URL::get_url() const {
    return url;
}

// Returns body of HTTP response
string URL::get_body() const {
    stringstream ss;
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&ss);
    int err = curl_easy_perform(curl);
    if (err) {
        cerr << "could not grab url " << url;
        return "";
    } else {
        return ss.str();
    }
}

/*
 C <-> C++ "bridge". A callback with this signature is needed by curl.
 - See secion "CURLOPT_WRITEFUNCTION" at
 http://curl.haxx.se/libcurl/c/curl_easy_setopt.html
*/
size_t
URL::curl_callback(void* source_p,size_t size, size_t nmemb, void* dest_p){
    int realsize=size*nmemb;
    string chunk((char*)source_p,realsize);
    *((stringstream*)dest_p) << chunk;
    return realsize;
}

// Examples of use
int main() {
    URL u("http://slashdot.org/");
    cout << "From " << u.get_url() << ":" << endl << u.get_body() << endl;

    u.set_url("http://troels.arvin.dk/");
    cout << "From " << u.get_url() << ":" << endl << u.get_body() << endl;
}